I've honestly never heard them called that before. Growing up in Alabama they were always called "Cast-Iron Skillets". I'm not complaining, I'm just curious if this is a regional/dialect type thing (like having a can of "pop", "soda" or "coke").

Skillet is only used for small pans in my experience (up to a span across). Larger than that, they're frying pans or pans. The people I know who use seasoned cast iron frying pans typically have huge ones they take camping... I can't imagine someone calling those a skillet.

If I recall correctly my grandmother's skillet was about 9 or 10 inches across. I've just never heard the term "cast iron pan" before, regardless of the definition of "pan" or "skillet". The big black iron thing in which we cooked and was seasoned was a skillet. I still remember when my grandmother bought a new one to supplement the older one's cooking duties. She made us build a big fire and toss the new one in and burn it. IIRC after the fire she coated it with an oil and put it away. And heaven help you if you ever made the mistake of thoroughly cleaning it, as I did.